Dental grinding means



Dec. 2, 1958 B, WEIGELE DENTAL GRINDING MEANS Filed Feb. 26. 1953 &

2 4 2 I 4 in United States Patent DENTAL GRINDING MEANS Bruno Weigele,Frankfurt am Main, Germany Application February 26, 1953, Serial No.339,088

Claims priority, application Germany February 26, 1952 1 Claim. (Cl.32-58) The invention relates to the grinding of teeth for the fitting ofa prosthetic part, such as for example, a jacket crown, three-quartercrown or the like, in the mouth of the patient by using a grinding band,wherein the tooth undergoing treatment serves as a tensioning elementfor the grinding band.

The invention has as an object the task of making it possible for thedentist to achieve an accurate grinding, both with respect to a specificsurface quality and to geometrical shape, such as was not possible withknown rotating grinding bodies which have hitherto been used. Theabrasive action of the rotating grinding bodies which are now used isonly intermittent, and corners and edges can remain which aredisadvantageous to the finished work. This may, for example, lead to abreak when jacket crowns of porcelain are being fitted and, with metalcrowns, projecting corners are left. Crown rims which project cause,however, chronic inflammation of the gums (paradentosis) and caries inthe rim of the tooth. On the exactitude of the edge finish in toothworkings, there depends in turn the fineness of the cement joint; thefiner the joint is, the longer the life of the repair work will be.

The invention provides for employing a readily usable flexible stripband of paper, linen, metal, wire cloth or the like, provided with anabrasive coating, the free ends of the said strip band being providedwith securing members, such as for instance, metal bushes; the band maybe coupled, bent in a semi-circular looped shape, to a dental hand-pieceby means of which the grinding band, acting as a loop for carrying outthe grinding work, is set in reciprocating movement along asemi-circular path. This strip band, the ends of which are provided withsecuring members, may either be fashioned as a straight strip or as astrip having a more or less strongly marked angular shape.

It is known to use, for grinding work, strips of paper, linen or metalprovided with a grinding surface which strips are held and guidedmanually and are moved to and fro in the spaces between teeth such as,for example, for the purposes of polishing tooth fillings.

A device is also known for the same purpose by means of which astrip-shaped grinding band is reciprocated mechanically. With both theknown grinding bands formed as strips, a controlled grinding such asprovided by the invention is, however, not possible and is also notintended, as the use thereof should and can only be to polish fillingsat the contact surfaces of the teeth.

Finally, for grinding tooth stumps in a patients mouth, a device wasproposed with which it was planned that the grinding should be carriedout by rotating an endless grinding band. This band is set in rotationalmovement by a toothed-wheel gearing enclosed in a housing; it istensioned about guide rolls and is adapted to be arranged about thetooth stump, which serves as a tensioning element. This device, however,has not been introduced into practice, for owing to its size, i. e.owing to lack of space in the patients mouth, it cannot be put into use,and it also does not make it possible to work from all sides on thetooth undergoing treatment. Rotating grinding bodies have thereforeremained in use up to the present for the work described in theforegoing.

As compared with the aforesaid proposed devices, the use of a strip bandbent in the form of a semi-circle, which is the basis of the presentinvention, gives in the final finish in conjunction with the surfacecontacting the tooth stump to be treated an exact rim finish such ascould' never be achieved with present methods of grinding. In thepreparation of a jacket crown and three-quarter crown, there isconsiderable difficulty in the finishing of the two adjacent sidesurfaces on the 'success of which finishing the later quality of thepreparation depends.

The use of a looped shape strip band makes possible the surfacetreatment of three sides of a tooth simultaneously, and the said toothsurfaces are, according to the invention, necessarily or to some extentautomatically ground in a parallel manner. Such treatment has hithertobeen dependent on the visual judgment of the dentist. Moreover, thesimultaneous treatment of three side surfaces of a tooth has the greatadvantage of saving a considerable amount of time as compared with thehitherto customary grinding method using rotating grinding bodies, withwhich only one surface or side of a tooth could be treated at a time.

The use of a grinding band according to the invention has a furthergreat advantage in that the elastic grinding band makes scarcely anynoise. In contrast thereto, a grinding method using rotating grindingbodies is accompanied by a noise which is agonizing and almostunbearable and makes many dentists shorten the grinding process at theexpense of the accuracy of their work. Moreover, it is much morepleasant for a patient if the grinding process is carried out with thegrinding band according to the invention, for the patient does not haveto keep his mouth Wide open, as was necessary with the hitherto employedgrinding means.

The grinding band according to the invention is shown in variousconstructional forms in the drawing, which also shows the manner inwhich the said grinding band is used:

Figure 1 shows part of a set of teeth with a ground tooth stump,

Figure 2 shows a ground tooth stump for the fitting of a three-quarter.crown,

Figure 3 is a View of a strip band fashioned with a markedly angularshape,

Figure 4 is a view of a strip band bent at a small angle,

Figure 5 is a side view of Figure 4,

Figure 6 is a side view of the strip band in a looped shape,

Figure 7 shows the connection of the strip 'band to a dental hand-piece,

Figure 8 is a view in the direction of the arrow X of Figure 7,

Figure 9 shows a further connection of the strip band to a dentalhand-piece, and

Figure 10 is a view of the arrangement of the loopshaped grinding bandon the dental hand-piece.

The strip band 1 consists of a flexible material, for example, linen,metal, wire cloth or the like. The strip band may be fashioned as astraight strip, but it may also, as Figures 3 and 4 show, be given anangular shape to a greater or less degree; in fact, the shape of thestrip is adapted to the type of tooth which is to be ground and to thedesired preparation, i. e. jacket crown, cap crown or three-quartercrown, etc. The strip bands are therefore readily adapted to theindividual types of teeth. The term readily adapted should be understoodas meaning that the dentist can have in stock or in readiness a numberof grinding bands 1 which are suitably adapted to the various types ofteeth (incisors, canine and molar teeth) and'to' the type of preparationdesired, i. e. jacket crown, c'ap' crown, three quarter' crown, etc., sothat depending on what tooth is to be treated the suitable band isfitted on to the dental hand-piece.

The free ends of the strip band 1 are provided'with securing memberssuch as, for instance, metal bushes 2, by which the band, which has beenlooped into a semicircular shape (Figures 6, 8 and 10), may be attachedto the dental hand-piece, the connection being effected by merelyfitting the bushes 2, for example, over the 'fingers 4 projecting fromthe hand-piece 3, said fingers being set in reciprocating movement inknown manner so that the band 1 is also made to reciprocate. Inconnection with the fingers 4, there are expediently provided severalsecuring parts 5 (Figure 8) for the attachment of the band 1, thusalfording the possibility of compensating for the size of the tooth,that is, of altering the angle of the loop. The grinding band may alsobe disposed about a roll (for example, a 3, 5, or 7 mm. diameter) andsecured on a pin of the said roll. The roll may expediently be providedwith a groove. First the tooth is roughly ground in the usual way andthen further ground in the desired manner with the grinding bandaccording to the invention. The rounding off of the four corners of thetooth, which at present takes two-thirds of the time taken by the wholetreatment process, is automatically achieved accurately and withouttrouble, by using the grinding band according to the invention, in oneto two minutes as compared with the thirty minutes and more previouslyrequired.

. The grinding band may be used for many purposes, 351101 the separatingof two teeth. The instruments at present in use for this purpose maytherefore be dispensed with. The grinding band may be operated frombehind (palatal or labial side) or from in front (labial or buccal side)of a row of teeth. It can be used on the front surface of the tooth andalso on the rear surface; that is, it can be used on all sides. This isachieved by using a fork-shaped driving means to which the grinding bandis attached by metal bushes 2.

The grinding surface layer of the band 1 may be variously chosen asregards fineness.

The use of the strip-shaped grinding band 1 according to the inventionfor grinding the rear surface of an incisor from the outside is shown byway of example in Figure 9.

I claim.

An instrument for efiecting an abrasive dental treatment comprising apair of movable parts adapted for reciprocating motions in approximatelyparallel directions, a strip-shaped band of a flexible material, agrinding material covering at least part of said band, and bushingsarranged, respectively, at the ends of said band and connected with themovable parts so as to apply to said band a reciprocating motion in thedirection of said reciprocating motions of said movable parts of thedental instrument, said strip-shaped band including a portion ofenlarged width and end portions extending oppositely and angularly awayfrom the portion of enlarged width.

References Cited in the file of this patent UNITED STATES PATENTS758,422 Crenshaw Apr. 26, 1904 1,147,594 Ball July 20, 1915 1,201,875Russ Oct. 17, 1916 1,379,489 Taylor May 24, 1921 1,880,617 White Oct. 4,1932

